Liquid crystal displays gradually become critical roles of consumptive electrical products, which are widely applied in displays of devices such as mobile terminals with high image resolution and color screens. The requirement of the display quality on the liquid crystal displays is increasing due to the higher demand on visual experiences. And the highly dynamic contrast technology is gradually grown to be the development trend. The dynamic contrast ratio of displays and the contrast ratio of an image developed by eyes in a single shot are basically approaching, which can enhance the resolution of brightness and dimness of displays.
The currently adopted technology is the dynamic spectrophotometry, which is dividing display regions and backlight into multiple respectively corresponding sub-regions. Effects such as higher brightness, dimmer dimness, enhancement of the dynamic contrast ratio of various sub-regions, etc. can be achieved by combination of backlight adjustment and gray-scale control according to the range covered by the brightness of display images in the sub-regions. The conventional backlight module is a direct-lit backlight module, which adopts a certain amount of emitter arrays to make the light guide plate to form the sub-regions as many as possible, resulting in relatively good effects regarding to division of image details and control of brightness. But as the light emitter (e.g. LED, etc.) occupies a certain space, and the light emitting angle has a certain spreading property, relatively long light mixing distance will be required to achieve even distribution of light, leading to the thickness of the direct-lit backlight module to be relatively thick, which is merely suitable for a display insensitive to the thickness and cannot be widely used in liquid crystal displays.